The field of smooth muscle regulation is growing rapidly and there is an increasing need felt among research workers in it to communicate. Recent national meetings have been too broadly focussed and too scattered for this purpose. Even smaller meetings such as the Gordon Conferences and FASEB Summer Conferences usually cover many subjects so that only one session can be devoted to a single topic such as smooth muscle. As a result, introductory or overview lectures are given repeatedly while in depth discussions are rare. This symposium is designed to focus on the regulatory mechanisms in smooth muscle. Ample opportunities will be given to conferees to survey the field from both physiological and biochemical viewpoints. A full session will be devoted to thin filament regulation in smooth muscle, which is emerging as an important problem. We feel that such a meeting is both appropriate and timely, and will be attended with high enthusiasm.